In recent years, in vehicles, various systems, as well as the engine and braking system, are electronically controlled, and a network is configured in the vehicle in order to perform data communication between the systems. In addition, data communication is widely performed between the systems in the vehicle and other vehicles or a data center outside the vehicle using, for example, road-to-vehicle communication and vehicle-to-vehicle communication, in order to acquire information outside the vehicle, such as traffic information around the vehicle. Patent Literature 1 discloses a technique in which a gateway device is provided between an information system network and a control system network in the vehicle, the state of each of an information system and a control system is periodically monitored, access control is performed to break or convert access to the information system and the control system when a mismatch occurs between the information system and the control system during cooperation therebetween, thereby associating the information system with the control system without damaging the stability or safety of vehicle control.